My new luminance L3 filter from astronomik came this week. Its going to replace my ZWO luminance filter. I have added a picture to show the difference.
The main issue was I was getting bad star bloat on blue stars using my ED72. The cause is the glass isn't blue corrected. So trying to find a cheap solution to fix.
So the test picture taking though smoke from the Australian fires shows that the new filter does reduce star bloat. If its enough I don't know. If I combine this with the Astronomik deep sky RGB set it could produce some very nice colour images. As the Astronomik blue filter stops at the same cutoff point as the LUM L3 does.
I found similar with my Evostar 72, I am just using the ZWO UV-IR filter and it made a significant improvement. Using an OSC camera and software that automates focus it made quite a difference as the excessive bloat with no filter at all would whack the focus routine a little.